In a lab devoted to increasing healthy lifespans, the transplant anti-rejection drug rapamycin showed unexpected health benefits and increased survival in a mouse model of a fatal mitochondrial defect. Children with the untreatable condition suffer from brain damage and muscle weakness, and rarely live beyond 6 or 7 years. The drug enables the body to bypass the mitochondrial defect by switching its metabolism to burn fats and amino acids instead of glucose, and thereby reduces toxic byproducts.View full story